Blading for steam and gas turbines



R. wA Nn 1,803,223

April .28, 1931.

BLADING FOR STEAM AND G AS TURBIIINBS Filed Dec. '23, 1 29 3Sheets-Sheet 1 April '28,. 1931; R. WAGNER BLADING FOR STEAM AND GASTURBINES Filed D80. 23; 1929 3 Sheets-Sheet 2 Q Apfi] 28, 1931. WAGNER1,803,223

BLADING F OR STEAM AND GAS TURBINES .Filed Dec. 23. 1929 s Sheets-Sheeta By. a.

Patented Apr. 28, 1931 UNITED STATES RUDOLF W'AGNER OF HAMIBURG,GERMANY,

BLADING FOR STEAM AND GAS Application filed December 23, 1929, SerialNo. 416,169, and in Germany Noveniber r, 1927.

This invention has for its object to provide turbine blading whichappears to be best adapted particularly for the first stage of highspeed, high and highest pressure steam or gas turbines with a view togreat safety of operation andalso gives with turbines for relativelysmall quantities of steam and small outputs a higher efiiciency thanbladings used heretofore.

For the solution of this problem the pres ent invention makes use of aPelton-like blading in the double bucket form with radial outeradmission as is already known in water turbines and also in steamturbines, for exa1nple,'in the Riedler-Stumpf-turbine or a similarrecently proposed construction (by Zagorski) with radial outer admissionand axial flow through a double bucket, the buckets on the outsidepartially shrouded by two end-rings. I

By the use of this type of blading the object aimed at is to introducethe hot fluid medium at the middle of the turbine casing, so that aconsiderably less flow of heat takes place through the rotor and thecasing to the bearings than with axial admission from one end of theturbine. This is particularly important with the use of high superheatedsteam and high numbers of revolution of the turbine'such as necessarilyresult with high pressure steam. Also the double flow Peltonbladingpermits convenient attainment of lower stufling box pressures by afollowing second stage on both sides of the Pelton-wheel than with asingle flow turbine, whereby on the one hand the safety of operation isfurther increased and on the other hand the loss of steam from thestufiing boxes is diminished.

The above mentioned Pelton-like 'blading 0 arrangements have, however,on the other hand, the drawback that in consequence of the open pockets,as, for example, in the Riedler-Stumpf-turbine, where they overlie oneanother at the periphery of the rotor in 5 roof-tile fashion, they causeexcessive loss of work by formation of eddies. On the other hand withthe afore-said Riedler-Stmnpfturbine and also with the above mentionedconstruction by Zagorskithe fluid medium endures from the exit from thenozzle up to the blade in the-longitudinal section of the turbine asudden devlation of 90 (tangential inlet and axial outlet), so thatnaturally very large losses result in the blade due to shock and eddies.

These drawbacks are overcome by the present invention by reason that thecentre lines of the two channels for the fluid medium formed by thedouble bucket diverge towards the centre of the shaft, preferabl at anacute angle to the plane of the whee and at the same time the passagesare closed at the sides in such wise that the outer sides of the bladingform a closed smooth rim, i. e. the pockets are not open as in theRiedler-Stumpf-turbine and no rivet heads project as in theZagorskiturbine.

This form of construction at the same time offers conveniently thepossibility of producing the shroudsor end-rings. integral with theblades, the individual sections of the shroud-rings being milled on theblades and so formed that they fit one another without leaving gaps.

In the accompanying drawings there are 7 shown in Figs. 1 to 7 severalembodiments of the invention.

Fig. 1 is a section through the wheel rim and the nozzle.

Fig. 2 shows a development of asection of so the rim through the bladeson the line AA of Fig. 1.

Fig. 3 showsa development of a sectione of the periphery on the line BBof Fig. 1.

Fig. 4 is a side elevation looking in the direction of the arrow X inFig. 1. v

Fig. 5 is a to plan showing the blading. Fig. 6 shows 'agrammatically inlongitudinal section one embodiment of a double flow turbine withPelton-blading on the first. stage connectednvith two axial admissionrotors as second stage.

Fig. 7 shows a modification of the new form of bucket in cross sectionthrough the rim of the rotor.

In Fig.- 1 a denotes the rotordisc, I) the blade according to theinvention, cc and d-J the centre lines of the two passages for theoperating fluid. These centre lines are "in thePresent/instarrcepositioned preferably sita tes a greater ateral deviation of the jetonissuing from the nozzle and entering in the blades. Theoretically aparallel position of the two centre lines 0-0 and would be mostfavorable, but in this case the formation of an unim ded exit from theblades presents difliculties.

In the example illustrated the two assages formed by two succeedingblades om the inlet point of the operating fluid, gxiting fromthe'nozzlee, are united for a certain art of their length to a single channel,while yondr this point up to the outlet of the passages they extendapart. There is thus formed on the pressure side of the blade a centraledge 11 by which division of the stream of t 0 operating fluid iseffected and promoted. The purpose of this arran ement is to diminishthe friction losses as ar as possible as compared with'a constructionin-w 'ch the two form.

assages for the fluid medium are separate rom the beginnin Also thetotal breadth of blade an accor gly the ventilation loss issomewhatdiminishe In the construction illustrated the pressure sides of theblades present surfaces of rotation, being milled out by a milling toolf with a bulbous head g (shown by chain-dotted lines in Fig. 3), theaxis of which miller is guided ppendicularly to the central plane of theui assages. .The rear side of the blades may a so be worked by a similarmilling tool with a bulbous head for forming the extensions h.

It is advantageous-for the flow'of the op erating fluid to well-roundoff the bulbous head of the milling tool at the corners (even tocomplete semi-circular form) 'so that the passages for operating fluidare of rounded cross section es ially on the pressureside of the bladesan therefore ofler less skin frictional resistancethan passages ofangular To facilitate the construction of the denble bucket, the bucketscan be divided in the} central plane DD of the wheel. -with the use of ablade root k disposed p'erpendicu "'larly to the plane of the wheel, andshaped I the plane'of thew eel is es for example, like asa -tooth,indica in the drawin and as shown in Figs. 1-4,

the two ,half b ades'. can be conveniently inserted independentlyintothe-wheel rim;

Theroot k di perpendicularlyto ially adapted for .the reaiect for thefor the resent t of bl son that? the wh e f su whole to the centrifugalaction of the blades, necessitating a less breadth of the wheel-rimandless spreading of the two passages for the fluid medium towards thecentre. of the shaft than with the use of the more usual hammer headroot to be inserted longitudinally'in the rim. In order to di-' minishthe spreading of the passages for the operating fluid the root can betapered on at both sides as shown in Fig. 1.

to lhemode of fixing the blades shown in Figs. 1 and 4 has also thadvantage that the otherwise usual look at, he point where the bladesare introduced, which is articularly dangerous with high numbers ofrevolution is dispensed with in that in general each blade can beinserted independently of the others. For the purpose of attaining alaterally closed smooth Irieripher there are milled in the example iustrated o blades extensions'h (Figs. 3, 4.and 5), which to the recessesinthe side wall of the blades behind the same. After insertion of theblades in the wheel rim they can beround at thersides in order to attainan absoutely smooth surfaceand to diminish the frictlon losses to aminimum.

,In. the exam le'ef constructionof a doubleflow steam tnr ineaccordingto Fig. 6, m dcnotes the rotor of the first sta e1 provided with thepresent Pelton-bladlng, behind which on each side is or are a rotor n orseveral rotors in order to diminish as far as possible the pressurebefore the stu g boxes It will be reco ized that for this purpose tlibnew t pe of b ading not only on account of its a ove mentionedadvantages, besides which may beincluded the absence of axial thrust,constitutes a very suitable means for constructing such a double-flowturbine especially for high superheated-high pressure steam and for hi hnumbers of revolution, operatingxpp to t e highest steam-tem eratures,to safe in operation and with igh eflicicncy, because for such a turbinea minimum flow of heat towards the bearings is an indispensablecondition.

7 The transference of the operating medium fromthe first to the'secondstage is facilitated if the diameters of the circles D formed by theoutlet openings of the Peltonblades are lar er than the mean diametersD, of the folfowin stage, is that curves'into the gui e-passages Z resut. o

The subsequent rotors n may be provided with blades 1n usual manner, forexample, with radiall disposed blades with axial admission, as s own in-Fig. 6; further they may n the backs of the entler be combined also withvelocity stages using wheel m.

Besides the example shown in Figs. 1 to 5' the present system ofPelton-bladin can be constructed also otherwise and can combined withother types of'blading withoutdeparture from the scope of the invention.

Thus, for example, the centre lines a c and dd of the two passages forfluid according to the .examples in Fig. 7 can be curved according to acertain radius from the external point in order to divert the fluidquicker towards the. sides, or to make the beginning of the passages forthe operating fluid exactly or approximately radial. course in this,case the construction of the blades is more difiicult than in theexamples shogvnin Figs. 1 to 5, in that for the pressure side there willbe used instead of disc miller ahead miller r with a head rounded inaccordance with the transverse profile of the passages for the operatingmedium, which miller is moved according to a templet against thepressure side of the blade and whose axis is moved at thesame time onthe arc aboutth'e centre 0.

I claim p 1. A blade for steam or gas turbines having curved doublepassages for radial outer admission in which the center lines of the twopassages for'the operating fluid diverge towards the axis of the turbineshaft and the passages are so formed that the outer sides of the bladepresent aclose d smooth rim.

2. A blade for steam-or gas turbines hav.'- ing curved double passagesfor radial outer admission in which the center lines ofthe two passagesfor the operat' fluid diverge to- 4 wards the axis of the turbine shaft,said two passages being united for a part of their length so as to forma single panel and extending apart beyond this point totheir outlets andthe said passages being so formed in the blade that the outer sides ofthe blade present a closed smooth rim.

3. A blade for steam or gas turbines having curved double passages forradial outer admission in which the center lines of the two passagesfor-the operating fluid diver e towards the axis of the turb ne shaft,said passages being located one upon each side of the central plane ofthe turbine wheel and the passages being so formed that the outer sidesof the blade present a closed smooth rim. i

admission.

7. A blade for steam or gas turbines having curveddouble passagesforradial outer admission in which thecenter lines of the two passages forthe operating fluid diverge towards'the axis of-the turbine shaft, saidblade being provided with a saw-toothed root adapted to be insertedtransversely into the rim of the wheel and the passages in said bladeare so formed that the outer sides of the blade present a closedsmoothrim.

8. A blade for steam or gas turbines having curved double passages forradial outer admission in which the center lines of the two v passagesfor the operating fluid diverge towards the axis of the turbine shaft,the portion of the blade in back of the pressurecontacting surfacesbeing formed so as to provide a cooperating surface with said passagesin an adjacent blade and the passa es being so formed that the outersides of t e blades present a closed smoothrim.-

.9. A blade for steam or gas turbines having curved double passages forradial outer admission in which the center'lines of the two passages forthe operating fluid diverge towards the axis of the turbine shaft, thepassages being so formed that the outer sides of the blade present a'closed smooth rim and J said outer sides being extended =rearwardl'y toform portions of the sides in an adjacent blade so as to form completepassages.

In testimony whereof I have signed my name to this specification.

RUDOLF- WAGNER.

4. A blade for steam or gas turbines hav- I ing curved double passagesfor radial outer admission in which the center lines of the two passagesfor the operating fluid are disposed at an inclination to one anotherand diverge towards the axis of the turbine shaft and said passages areso formed that the admission in which the center lines of the two outersides of the blade smooth rim.

5. A blade for steam or gas turbines having curved double passages forradial outer present a closed passages for the operating fluid divergetowards the axis of the turblne, shaft, sai

sages being curved in cross section upon the pressure side of the bladeand sald passages

